Abstract: The invention relates to a portable device with access to several instances such that each of the instances performs an operation in response to a wireless data exchange with the portable device. The portable device comprises a data processing unit and a memory that stores a public key, a private key and a certificate. The portable device is further configured to transfer the certificate and the public key to a first instance. The first instance is configured to receive the first public key and the first certificate from the first portable device. The first instance is further configured to receive a signature from the first portable device, to decrypt the signature with the copy of the first public key so as receive a code, to compare the code with the random challenge and to perform the operation only if the code and random challenge match.

Abstract: A laser system is provided that includes a laser unit, an incoupling means for coupling the laser radiation into a light-guide, and an outcoupling means for coupling the laser radiation out from the light-guide. A data transmitting means is coupled to the incoupling means or outcoupling means and produces optical signals which are coupled into the light-guide via the incoupling means or the outcoupling means. These optical signals are received by a data receiving means at the other end of the light-guide. The laser system can be used for realizing a data communication between the hand-piece and the stationary unit of the laser system in the case of which additional cables between the hand-piece and the laser are not necessary for transmitting data.